Jekyll Plugin Error Handling During Build

Direct answer

Jekyll does not emit a completed site when an uncaught plugin exception occurs during generation. By default, the build stops and the Jekyll CLI exits with a non-zero status. The build can proceed with a potentially incomplete site only if the plugin catches the exception itself or a hook swallows it; Jekyll cannot detect internally handled errors and may finish while missing pages or assets.

Confirmed facts versus likely explanation

Item	Status	Details
Uncaught plugin exception	Confirmed	Aborts generation; non-zero exit; no success message.
Configuration directive to force failure	Confirmed absence	No _config.yml directive enforces failure; failure is the default for uncaught exceptions.
strict_front_matter	Confirmed unrelated	Controls invalid YAML front matter, not uncaught plugin exceptions.
--trace	Confirmed	Prints full backtraces and re-raises in CLI error paths; does not create a continue-on-error mode and is not, by itself, proof that the build halted.
Plugin catches its own error	Likely explanation	Accounts for reports that the build continues after a plugin error is logged.
Version and plugin-type variance	Uncertain	Behavior may differ by Jekyll version and by whether the exception is raised in a generator, converter, hook, tag, or during plugin loading.

Verification steps

1. Record the installed version: jekyll -v
2. Add a deliberate exception to a plugin generator or tag, then run:

   jekyll build
   echo $?

3. Confirm a non-zero exit and the absence of a success message. Log output alone is not sufficient evidence of completion.
4. Repeat with jekyll build --trace and compare the backtrace. Trace shows propagation but does not by itself prove the build stopped.
5. Inspect the destination folder only after a non-zero exit. Incomplete output with a zero exit means the plugin swallowed the error.

Missing diagnostic detail: which Jekyll version are you running? Version-specific handling can change whether a workaround is needed. Verify this behavior against your installed version before relying on it in CI.